1. Field of the Inventions
The present inventions relate generally to peristaltic pumps. More particularly, the present inventions relate to a uniquely-configured peristaltic pump that can include a maintenance mode for facilitating safe replacement of pump tubing.
2. Description of the Related Art
A peristaltic roller pump typically has three or more rollers, but may have other configurations. The rollers are spaced circumferentially evenly apart and are mounted on a rotating carrier that moves the rollers in a circle. A length of flexible tubing is placed between the rollers and a semi-circular wall. In medical applications, the tubing can be a relatively soft and pliable rubber tubing. For relatively high pressure industrial applications, however, the tubing can be exceedingly durable and rigid, albeit flexible under the high pressure of the rollers.
In use, the rollers rotate in a circular movement and compress the tubing against the wall, squeezing the fluid through the tubing ahead of the rollers. The rollers are configured to almost completely occlude the tubing, and operate essentially as a positive displacement pump, each passage of a roller through the semicircle pumps the entire volume of the fluid contained in the tubing segment between the rollers.
As a positive displacement pump, relatively high positive pressures (e.g., 125 psi) can be generated at the pump outlet. Peristaltic roller pumps are typically driven by a constant speed motor that draws fluid at a substantially constant rate. Over time, the high pressures at the pump outlet can wear on the tubing and result in the development of small pinholes in the tubing. If unnoticed, the pinholes can grow and eventually result in failure of the tubing.
Ruptured tubing can lead to internal leakage and the cessation of proper function. When the pump is used to move a corrosive chemical, such as chlorine, internal leakage can be particularly hazardous. As the chemical comes into contact with the pump components, the pump may become irreparably damaged. This is a serious shortcoming because the costs associated with replacement of the pump can be very substantial.
When tubing is replaced, the placement of the tubing underneath the rollers of the pump can be a very difficult task, especially in industrial applications. Typically, a user will attempt to replace the tubing by connecting one end of the tubing to one of the inlet or outlet ends of the pump and then forcibly bending the tubing around the rollers of the pump. This task is extremely difficult considering the narrow spacing between the rollers and the pump wall.